Short recoil breech actuating mechanism



Jan. 9, 1968 G. D'ANDREA 3,362,292

SHORT RECOIL BREECH ACTUATING MECHANISM Filed Sept. 21, 1966 5 Sheets-Sheet l l6 II I I2 lao a r FI' L ATTORN EY Jan. 9, 1968 G. DANDREA 3,352,292 7 SHORT RECOIL BREECH ACTUATING MECHANISM Filed Sept. 21, 1966 5 Sheets-Sheet 5 INVEh ITOR E in] 111111: IIAnElI'EU;

BY 22 WW ATTORNEY Jan. 9, 1968 G. D'ANDREA 3,362,292

SHORT RECOIL BREECH ACTUATING MECHANISM Filed Sept. 21, 1966 5 Sheets-Sheet 4 ET- 22 L2 l8 INVEIIQTOR 22 Ezul'iunu DAnEiTau.

J4 S I I m ATTORNEY a Jan. 9, 1968 G. DANDREA SHORT RECOIL BREECH ACTUATING MECHANISM 5 Sheets-Sheet 5 Filed Sept. 21, 1966 INVEIIHTOR EiuliunnDAnElreu 8 BY I I ATTORNEY United States Patent 3,362,292 SHORT RECOIL BREECH ACTUATING MECHANISM Giuliano DAndrea, Troy, N.Y., assignor t0 the United States of America as represented by the Secretary of the Army Filed Sept. 21, 1966, Ser. No. 582,198 15 Claims. (Cl. 89-24) This invention relates to artillery weapons having a recoiling breech with a vertically slidable breechblock therein adapted to be returned to the closed position thereof by a torsion leaf spring and is more particularly directed to improved means for energizing and releasing the spring within a minimum portion of the recoil and counterrecoil travel of the breech.

Inasmuch as modern military operations require more and more mobility in both personnel and weapons, the artillery of yesterday is no longer capable of adequately coping with the rapid and unexpected changes in location of the various targets normally encountered in combat. While the ease of operation and the rate of fire of artillery weapons has been considerably improved by the utilization of a recently developed semiautomatic breech mechanism which employs the counterrecoiling energy of the recoiling parts to open the breech for extraction and ejection of the fired case, the same degree of success has yet to be achieved in providing these weapons with sufficient mobility to track rapidly moving targets. According- 1y, it has been suggested that the best solution to this problem is the utilization of ammunition with propellant charges which will fire the projectiles to predetermined ranges. However, considerable difiiculty has been encountered in firing both short and long range projectiles from a recoiling breech type of weapon.

This is particularly true in a current howitzer gun wherein the counterrecoil travel of the breech is utilized to actuate a vertically slidable breechblock to the open position thereof while simultaneously loading a torsion leaf spring to return the breechblock to the closed position thereof upon the insertion of a new round into the firing chamber as illustrated and explained in US. Patent No. 2,756,635. While this type of howitzer can be utilized to fire ammunition with varying propellant charges designed to provide predetermined projectile ranges, the span between the maximum and minimum range which can be attained thereby is considerably limited by the necessity for a length of recoil travel which will insure sufficient counterrecoil energy to pull a follower through the particular cam path required to lower the breechblock to the open position. Although it would appear that an increase in the preload of the recuperators which serve to buffer the recoiling forces could add suflicient counterrecoil energy to the breech to permit a corresponding reduction in the minimum recoil travel which wouid be required, this approach has not been too successful in smaller caliber weapons inasmuch as the recoiling parts are gen erally too light to respond to the added counterrecoil energy without undesirable jumping and hopping.

Accordingly, it is a primary object of this invention to provide a howitzer of large caliber with a recoiling breech mechanism which will permit the firing of both long and short range ammunition at the option of the operator.

It is a further object of this invention to provide a breech actuating mechanism for a howitzer as aforesaid wherein the span between the minimum and maximum ranges of the projectiles fired therefrom can be substantially increased without the necessity for interfering with the normal recoil and counterrecoil of the breech.

Another object of the present invention lies in the provision of a breech actuating mechanism as aforesaid wherein the force required to energize the breech closing spring is reduced to a minimum in order to permit the firing of ammunition with an extremely low propellant charge.

A further object of this invention is to provide a howitzer recoil system wherein the desired reduction in the counterrecoil forces required to actuate the breechblock can be accomplished by energizing a torsion leaf spring during the initial portion of the recoil travel of the breech.

A final object of this invention is to provide reliable and compact means for actuating a vertically slidable breechblock in a recoiling breech mechanism wherein the length of the recoil travel of the breech varies in accordance with the range attained by the ammunition.

It has been found that the foregoing objects can best be achieved by mechanism in which a fixed cam is positioned in the path of a follower projecting from the outer end of a crank rotatably mounted in a housing depending from the underside of the breech ring on the breech end of the gun tube. Such housing is arranged to contain a torsion leaf spring which serves to raise the vertically slidable breechblock to the closed position thereof within the breech ring. One end of the torsion leaf spring is fixed within the housing while the opposite end of the spring is secured to the crank. Thus, during the initial portion of the recoil travel of the breech ring, the fixed cam acts on the follower to rotate the crank and wind the torsion leaf spring to the required extent. A pivotal latch is secured to the breech ring in position to receive and hold the follower at the conclusion of the winding rotation of the crank in order to prevent premature release of the torsion leaf spring.

As the breech ring counterrecoils to substantially th same point as that at which the winding of the torsion leaf spring was completed during recoil, the breechblock is automatically unlocked to drop to the open position required to permit the extraction and ejection of the fired case. During the remainder of the counterrecoil travel of the breech ring, the fixed cam pivots the latch to release the crank follower whereupon the torsion leaf spring is freed to lift the breechblock toward the closed position thereof until halted by the cartridge extractors. The insertion of a new round into the breech ring releases the extractors to permit the torsion leaf spring to complete the closing of the breechblock.

Since the foregoing arrangement lo'ads the torsion leaf spring during the recoil travel of the breech ring and latches such lo-aded spring until the breechblock has been fully opened to permit the ejection of the fired case, the operating cycle of the spring is reduced to a relatively small portion of the travel of the breech ring at the beginning of recoil and at the conclusion of counterrecoil. It is, therefore, possible to fire ammunition with a very light propellant charge since the recoil travel of the breech ring need only be enough to energize the torsion leaf spring. At the same time, ammunition with a very powerful propellant charge can be fired Without any adjustment 3 of the recoiling parts since the additional recoil travel of the breech ring will not afiect the operating cycle of the torsion leaf spring.

Further objects and features of the invention will be apparent from the following specification and the accompanying drawings which are for the purpose of illustration only and in which:

FIG. 1 is a right side view of the breech portion of a howitzer provided with the actuating mechanism of the present invention, shown in the position in which the breech is closed and locked;

FIG. 2 is an enlarged sectional view taken along line 2-2 of FIG. 1 to show the relationshi of the various components of the mechanism for actuating the breechblock;

FIG. 3 is a sectional view taken along line 33 in FIG. 2 to show the details of the manual operating handle and the engagement thereof with the shaft utilized to actuate the breechblock;

FIG. 4 is a section taken along line 4-4 in FIG. 3 to show the relationship between the breechblock unlocking cam on the manual operating handle and the locking plunger which retains the breechblock actuating shaft against rotation;

FIG. 5 is a view similar to that of FIG. 4 but showing the relationship of the parts after the handle has been rotated sufiiciently to unlock and lower the breechblock to the open position thereof;

FIG. 6 is a view similar to FIG. 1 but showing the parts in the position after the breech has been manually opened to permit the loading of a new round;

FIG. 7 is fragmentary side elevation of the breech actuating mechanism showing the position of the parts during the recoil travel of the breech after the crank has been rotated to energize the torsion leaf spring and after such spring has been latched to store the energy therein for subsequent release;

FIG. 8 is a view similar to that of FIG. 7 but showing the position of the parts during the concluding portion of the counterrecoil travel of the breech after the crank has lifted the breechblock locking plunger to permit the brecchblock to drop to the open position thereof;

FIG. 9 is a fragmentary section taken along line 9-9 in FIG. 2 to show the position of the breechblock operating lever at the conclusion of the opening of the breech;

FIG. 10 is a view similar to FIGS. 7 and 8 but showing the parts at the conclusion of counterrecoil after the latch has been pivoted to release the crank and thereby permit the stored energy of the torsion leaf spring to initiate the lifting of the breechblock; and

FIG. 11 is an exploded perspective view of the various parts utilized to energize and release the torsion leaf spring which lifts the breechblock to the closed position thereof.

Referring to the drawings and in particular to FIG. 1, there is shown a fragmentary portion of a howitzer carriage 12 in which a firing tube 14 is slidably mounted for recoil and counterrecoil travel. A breech ring 16 is suitably secured to the breech end of tube 14 and is provided with a vertical track 18 therein for slidably receiving corresponding rails 20 on opposite sides of a substantially rectangular breechblock 22. The lower end of breechblock 22 is interiorly recessed as best indicated at 24 in FIG. 9 and a pair of inclined slots 26 extend upwardly and forwardly along the opposite sidewalls of recess 24 for engagement with the ends of a transverse pin 28 fixed in the lower end of a bre'echblock actuating lever for a purpose to be hereinafter explained. An elongated extractor 32 terminating in a trunnion 34 at the lower end thereof, as seen in FIG. 8, is journaled into each of the opposite sides of breechblock 22 and extends upwardly through breech ring 16 in position to extract and eject a fired cartridge case in a conventional manner.

Extending transversely along the underside of breech ring 16 forwardly of breechblock 22 is a rectangular housing 36 having cylindrical lugs 38 and 39 depending from the opposite ends thereof to rotatably support a hollow shaft 40. A pin 42 is threadably secured in the righthand support lug 39, as viewed in FIG. 2, and extends into the interior thereof to engage in an annular groove 44 about the periphery of shaft 40 for retention thereof against lateral movement in housing 36. A hollow bushing 46 with a head 48 of enlarged diameter is adjustably mounted in the left hand support lug 38 of housing 36 and is retained therein against lateral movement by a pin 50 threadably secured in lug 38 for engagement with an annular groove 52 in bushing 46 in a manner similar to pin 42. Bushing 46 is normally locked against rotation in support lug 38 by a longitudinal plunger 54 slidably seated against a spring 543 in the end Wall of housing 36 to project therefrom into engagement with one of a plurality of stepped arcuate notches 58 formed in the exterior periphery of bushing head 48. Plunger 54 is vertically positioned in housing 36 to expose a portion of the outer end thereof above the periphery of bushing head 48. Thus, in the event rotational adjustment of bushing 46 is required for a purpose to be shown, this may be readily achieved merely by employing a suitable tool to depress plunger 54 against spring 56 sufficiently to disengage from notch 58. Bushing 46 can then be rotated to align with one of the other arcuate notches 58 and plunger 54 released to engage therewith.

Shaft 40 is diametrically enlarged as indicated at 60 to provide an annular retaining shoulder 62 which is sufliciently spaced from the inner end of bushing 46 to form a seat for the enlarged end 64 0f the actuating lever 30 which projects from the underside of rectangular housing 36. The exterior periphery of such seat is of rectangular configuration as indicated at 66 to mate with a correspondingly shaped axial hole 68 through the enlarged end of lever 30. Shaft 40 is additionally enlarged in diameter as indicated at 69 to provide a bearing surface engageable with the interior of lug 39. The extreme right end of shaft 40 is counterbored as indicated at 70 to rotatably receive a cylindrical arm 72 extending from one side of a hollow crank 74. The opposite side of crank 74 is provided with a projecting follower pin 76 having a roller 77 rotatably secured thereon by a pair of split retaining rings 79. As best illustrated in FIG. 2, bushing 46, shaft 40 and crank 74 are disposed in axial alignment to form a housing for a torsion leaf spring 78 consisting of a stack of individual rectangular leaves 80. One end of spring 78 is fixedly secured within the interior of bushing 46 by a transverse pin 82 passing through leaves while the other end of spring 78 is secured within the interior of crank 74 for limited angular movement by a transverse pin 84 threaded into crank 74 as indicated at 86 and extending therethrough to engage in an arcuate slot 88 formed along the interior periphery of counterbore 70 in the end of shaft 4t). A thin flexible cover 90 is pressed into a counterbore 92 in the outer end of the enlarged head 48 of bushing 46 to prevent the entry of dirt and other foreign matter which might be injurious to the proper operation of torsion leaf spring 78. At the other end of spring 78, similar protection is afforded by a cover plate 94 disposed within a corresponding counterbore 95 in the outer end of crank 74 and retained therein by a split ring 98 as best shown in FIG. 11. When crank 74 is rotated in a counterclockwise direction within shaft 40 as viewed in FIG. 1, spring 78 is torsionally wound in accordance with the degree of rotation imparted to crank 74. In order to provide for the reduction in the overall length of leaves 80 produced by the twisting movement thereof, the hole therethrough for retaining pin 84 is elongated as best indicated at 100 in FIG. 11.

The body of crank 74 is essentially of cylindrical configuration with substantially half of the exterior periphery being slightly reduced in diameter to form opposed transverse shoulders lllil. In addition, the larger diameter portion of crank 74 is bulged outwardly to a lesser width to form a cam surface 104 which extends along the periphery thereof to terminate at the junction thereof with transverse shoulder 102. The end of shaft 40 in which crank 74 is mounted is enlarged as indicated at 106 to substantially the same diameter as the body of crank 74 and is provided with a laterally extending operating lug 108 disposed in the rotative path of shoulders 102 on crank 74 so that rotation thereof can be transferred to shaft 40 as will be hereinafter shown. However, shaft 40 is normally locked against rotation by means of a transverse slot 110 across the exterior periphery thereof spaced clockwise of lug 108 as viewed in FIG. 11 and disposed to receive the free end of a vertically slidable plunger 112.

Plunger 112 is housed in a vertical hole 114 in a bracket 116 bolted to housing 36 above support lug 39 and extending out over enlarged shaft end 106. Retention of plunger 112 against rotation in bracket 116 is effected by a transverse pin 118 which passes through plunger 112 to engage in vertical slots 120 in opposite walls of bracket 116. A coil spring 122 is disposed in bracket hole 114 in Contact with the top of plunger 112 and is compressed thereagainst by a cylindrical cap 124 threaded into the upper end of bracket hole 114. Downward travel of plunger 112 is limited by the bottoming of the ends of pin 118 in slots 120. Plunger 112 includes a rectangular lug 126 extending outwardly from the lower end thereof toward lug 39 and a roller 128 projecting outwardly therefrom in a direction opposite lug 126 for purposes to be shown.

In order to initiate the semiautomatic operation of the howitzer, it is, of course, necessary to start with a round in the firing chamber. Accordingly, in order to load the first round, breechblock 22 must be manually actuated to an open position wherein the rear end of the firing chamber in breech ring 16 will be fully exposed. This is accomplished by an elongated charging handle 130 terminating in a ring-shaped lower end 132 which is rotatably fitted onto a cylindrical hub 134 integrally formed on support lug 39. The exterior periphery of the ring-shaped end 132 of handle 130 is provided with a radially projecting cam lug 136 and spaced clockwise thereof is a laterally extending dog 138 engageable in an arcuate recess 140 formed into the inner sidewall of the enlarged end 106 of shaft 40 as best shown in FIG. 3. The upper end of charging handle 130 is provided with a spring-biased release rod 142 telescopingly mounted therein and provided with a laterally projecting pin 144 designed to releasably engage with a downwardly opening hook 146 fixed to the side of breech ring 16.

With the parts in the position of FIG. 1, the manual opening of the breech is accomplished by releasing charging handle 130 from engagement with hook 146 and pulling such handle in a counterclockwise direction so that cam lug 136 thereon will engage the underside of lug 126 and thereby lift plunger 112 out of engagement with transverse slot 110 in enlarged end 106 of shaft 40. As handle 130 continues to be pulled, dog 138 thereon will engage with the end wall of arcuate recess 140 in shaft end 106 and thereby impart corresponding rotation to shaft 40. As a result, breechblock actuating lever 30 thereon is rotated so that pin 28 on the upper end thereof rides along inclined slots 26 in breechblock 22 to lower the latter to the fully open position of FIG. 6. As this is being accomplished, lug 108 on shaft end 106 contacts shoulder 102 on crank 74 and imparts corresponding rotation thereto which winds torsion leaf spring 78. As breechblock 22 is being lowered to the open position thereof, extractors 32 are automatically pivoted to temporarily lock breechblock 22 in such position. By this time, a stud 148 on end 124 of handle 130 has been brought into contact with a fixed bar 150 extending from the right end of housing 36 to prevent further rotation of handle 130 which can then be returned to the latched position of FIG. 1. The subsequent insertion of a round into the firing chamber of breech ring 16 automatically pivots extractors 32 out of the upward path of breechblock 22 to permit torsion leaf spring 78 to continue the lifting thereof to the closed position of FIG. 1.

However, in the event of any malfunction in the operation of spring 78, handle can also be utilized to lift breechblock 22 to the closed position thereof. This is rendered possible by a detent plunger 152 slidably retained in an arm 154 which projects outwardly from the side of ring-shaped end 132 of charging handle 130 to overlie a notch 156 out into the enlarged end 106 of shaft 40 in alignment with operating lug 108. A spring 156 surrounds plunger 152 between a flanged head 160 thereon and the top of arm 154 to normally retract plunge-r 152 against protruding from the other side of arm 154. Retraction of plunger 152 is limited by a cross pin 161 which passes through a transverse slot 163 therein into fixed engagement in charging handle arm 154. Thus, in order to lock handle end 132 to shaft 40, plunger 152 must be depressed to engage in notch 156 and held in the depressed position while handle 130 is being pushed forwardly toward engagement with fixed hook 146 on breech ring 16. This rotation of handle 130 will thereby rotate shaft 40 which will pivot operating lever 30 to cam breechblock 22 upwardly to the closed position thereof.

During semiautomatic operation of the howitzer, the rotation of crank 74 is effected directly instead of through the rotation of shaft 40 as in the manual opening of the breech. In order to accomplish this function, a bracket 162 is bolted to carriage 12 adjacent the right end of housing 36. Additional rigidity of bracket 162 is achieved by the provision of a transverse channel 164 across the front end thereof arranged to engage with a corresponding rib 166 on the rear end of carriage 12. Bracket 162 extends rearwardly and is cut away as indicated at 168 in FIGS. 1, 6 and 11 to provide a hook-shaped rear end 170 which includes a rearwardly and upwardly inclined cam surface 172 thereon facing cutaway portion 168. The forward end of bracket 162 is provided with a vertically extending rectangular passage 174 in which a release lever 176 is mounted for pivotal movement in a vertical plane. Lever 176 extends rearwardly beyond cutaway portion 168 and terminates in a reduced width portion 178 having a roller 180 fixed to the outer side thereof to extend out over crank 74. Bracket 162 is dimensioned so that when breech ring 16 is in the battery position thereof as shown in FIG. 1, follower roller 77 on crank 74 lies within the cutaway portion 168 and against the lower end of cam surface 172 therein.

Thus, upon the firing of a round by conventional firing means (not shown), breech ring 16 and breech tube 14 begin to recoil. Since cam bracket 162 is fixed relative to the recoiling parts, follower roller 77 on crank 74 begins to ride upwardly along cam surface 172 thereby imparting counterclockwise rotation to crank 74 which in turn winds torsion leaf spring 78 accordingly. In order to store the energy imparted to spring 78 until needed, a latch 182 is pivotally mounted on a pin 184 projecting outwardly from a plate 186 bolted to the outer end of bracket 116 as indicated at 188. Latch 182 is shaped to resemble a foot and is provided with a central arcuate guide slot 190 therethrough which originates at the toe and terminates at the heel in a relatively short and curved offset portion 182. Slot 190 and olfset portion 192 are both of suflicient Width to slidingly receive follower pin 76. A coil spring 194 with one end fixed in latch 182 at a point above offset portion 192 of slot 190 and the opposite end fixed in a vertical slot 196 in the end of latch pin 184 serves to rotate latch 182 in a clockwise direction. Spring 194 is housed within a cylindrical cover 198 fastened to latch pin 184 by a suitable split ring 200.

Thus, as crank 74 is rotated to wind torsion leaf spring 78, follower pin 76 follows the curve of arcuate slot 190 7 in latch 182. The rotation of crank 74 is terminated as follower roller 77 rides over the corner formed by cam surface 172 and the linear top surface of hook end 170. At this point, follower pin 76 has moved opposite offset portion 192 of arcuate slot 190 in position to engage therein as latch 182 is pivoted in a clockwise direction by spring 194. Since the bias of torsion leaf spring 78 when wound exerts a force which resists the exit of follower pin 76 from offset portion 192 of slot 190 and since latch 182 is normally biased in a clockwise direction, crank 74 is securely retained against the rotation which would permit torsion leaf spring 78 to unwind. In this position of latch 182, follower roller 77 will ride along the top of hook end 170 of bracket 162 during the remainder of the recoil travel of breech ring 16 required to effectively dissipate the force generated upon the discharge of the round in the firing chamber.

During the counterrecoil travel of breech ring 16, the breech remains locked until cam surface 104 on crank 74 contacts the underside of roller 180 on release lever 176 as shown on FIG. 8. As cam surface 104 passes under roller 180, lever 176 is lifted into contact with roller 128 to raise plunger 112 out of engagement with transverse slot 110 in enlarged end 106 of shaft 40. Since shaft 40 is now free to rotate, breechblock 22 will drop to the open position shown in FIG. 8 solely through its own weight. The resulting rotation imparted to shaft 44 through operating lever 30 thereon will bring operating lug 108 on shaft 40 into position for contact by shoulder 102 on crank 74.

As breech ring 16 continues to counterrecoil, the upper end of latch 1S2 strikes a projecting finger 202 at the top of the cutaway portion 16% in bracket 162 whereby latch 182 is pivoted in a counterclockwise direction to free follower pin 76 from engagement in offset portion 192 as best shown in FIG. 10. Thus, crank 74 is free to respond to the energy stored in torsion leaf spring 73 and rotate in a clockwise direction to engage operating lug 108 on shaft end 106 and impart corresponding rotation to shaft 40 which will rotate operating lever 30 thereon to lift breechblock 22 toward the closed position thereof. However, during the dropping of breechblock 22 to the open position, extractors 32 were pivoted to extract and eject the fired round from the firing chamber in breech ring 16. In this position, extractors 32 are disposed to block the rise of breechblock 22 beyond that shown in FIG. until a live round is loaded into the firing chamber. This will pivot extractors 32 out of engagement with breechblock 22 which will then rise to the fully closed position shown in FIG. 1, ready for another cycle of operation.

Inasmuch as the torsion leaf spring 78 in the above described invention is arranged to be wound during the initial portion of the recoil travel of the breech ring 16, the latter need only possess suflicient energy to force follower roller 77 along the length of inclined cam surface 172 on book end 170 of fixed bracket 162. Once torsion leaf spring 78 is latched against unwinding, breech ring 16 can begin to counterrecoil. It is therefore readily apparent that the required recoil travel of breech ring 16 is reduced to a minimum. For example, in a howitzer weapon of the type disclosed in US. Patent No. 2,756,- 635, the breech ring requires a minimum recoil travel of 7 inches to insure sufiicient counterrecoil energy to wind the torsion leaf spring, in comparison with the present invention in which only 2.8 inches of recoil travel is needed to perform the above function. Thus, the present invention enables the use of ammunition in which the propellant charge is designed to provide an extremely short projectile trajectory such as required in the firing of mortar type shells. Furthermore, the concept of loading the torsion leaf spring during the recoil of the breech ring is an important improvement in breech systems of this type inasmuch as the winding of the spring is accomplished at a time when the breech ring possesses maximum energy. In fact, the energy required to wind the recoil spring reduces the buffer action required of the recuperators, thereby 8 permitting a less violent counterrecoil of the moving parts which improves the life of the Weapon.

I claim:

1. In a large caliber gun having a stationary carriage supporting a recoiling breech including a vertically slidable breechblock adapted upon the unlocking thereof to drop to a fully open position, and torsion leaf spring means depending from the breech for returning the breechblock to the closed position thereof, the improvement in the means for winding and unwinding the torsion leaf spring means, comprising a rotatable crank connected to one end of the torsion leaf spring means, a follower projecting laterally from the side of said crank, a cam surface fixed to the stationary carriage in position to engage with said follower during the initial recoil travel of the breech, a latch pivotally mounted to the breech in position to engage with said follower at the conclusion of the rotation imparted to said crank and thereby prevent unwinding of the torsion leaf spring means, means for locking the breechblock in the closed position thereof during the entire recoil travel of the breech and during the counterrecoil travel thereof prior to the passage of said follower beyond said stationary cam surface, means for unlocking the breechblock to permit the dropping thereof to the open position, and means for pivoting said latch subsequent to the dropping of the breechblock to release said crank follower therefrom and permit the unwinding of the torsion leaf spring means to lift the breechblock to the closed position thereof.

2. The combination defined in claim 1 wherein said cam surface is provided by an upwardly and rearwardly inclined forward edge of a hook-shaped arm on a fixed bracket projecting from the stationary carriage to extend rearwardly alongside said crank.

3. The combination defined in claim 1 wherein said pivotal latch is a foot-shaped member having an arcuate guide slot centrally formed therethrough for passage of said crank follower, said guide slot originating at the toe end of said latch and terminating in a curved offset portion at the heel end thereof, and spring means normally biasing said latch to pivot said offset portion of said guide slot into engagement with said crank follower.

4. The combination defined in claim 1 wherein said means for pivoting said latch to release said crank follower comprises a finger projecting rearwardly from the stationary carriage for contact with the upper end of said latch above the pivot point thereof on the breech.

5. In a large caliber gun having a stationary carriage for supporting a recoiling gun tube terminating in a breech ring including a vertically disposed breechblock slidable between a closed and a fully open position, a hollow shaft journaled to the underside of the breech ring and provided with an actuating lever for returning the breechblock to the closed position thereof, and a torsion leaf spring contained within the hollow shaft with one end connected thereto for rotating the shaft to operate the breechblock actuating lever, the improvement in the means for energizing and releasing the torsion leaf spring comprising, a crank rotatably mounted in one end of the hollow shaft for connection with the free end of the torsion leaf spring, a follower pin projecting from the outer side of said crank, a bracket fixed to the stationary carriage to extend rearwardly therefrom alongside said crank, said bracket having an upwardly and rearwardly inclined cam surface therein engageable with said crank follower pin during the initial recoil travel of the breech ring whereby said crank is rotated to energize the torsion leaf spring, a latch pivotally mounted to the breech ring in position to engage with said crank follower pin at the conclusion of the rotation imparted to said crank and thereby retain the torsion leaf spring in the energized position thereof during the entire recoil travel of the breech and during the counterrecoil travel thereof prior to the passage of said follower pin beyond said cam surface in said carriage bracket, a rearwardly projecting finger on said carriage bracket for pivoting said latch subsequent to the dropping of the breechblock to release said crank follower pin therefrom and thereby permit the energized torsion leaf spring to rotate said crank, and means for transferring the rotation of said crank to the hollow shaft for operating the breechblock actuating lever to lift the breechblock to the closed position thereof.

6. The combination defined in claim wherein said means for locking the breechblock in the closed position thereof comprises, a bracket housing fixed to the side of the breech ring to extend outwardly over one end of the hollow shaft, a spring-biased retractable plunger vertically disposed in said housing to project from the bottom thereof, and slot means in the outer end of the hollow shaft engageable with the projecting end of said plunger to prevent rotation of said shaft.

7. The combination defined in claim 5 wherein said means for transferring the rotation of said crank to the hollow shaft comprises a transverse shoulder on the exterior periphery of said crank engageable with a lug projecting outwardly from the end of the shaft.

'8. The combination defined in claim 5 including a manual charging handle having a ring-shaped lower end rotatably mounted on the hollow shaft adjacent one end thereof, means for releasably latching the upper end of said charging handle to the side of the breech ring, cam means on said handle for unlocking the breechblock during the initial portion of the manual actuation thereof, means on said ring-shaped end for transferring the manual actuation of said handle to rotation of the hollow shaft whereby the unlocked breechblock is lowered to the open position thereof, and means on the hollow shaft for transferring the rotation imparted thereto by said handle to said crank for energizing the torsion leaf spring whereby the breechblock will be automatically lifted to the closed position during the return of said handle to the latched position thereof.

9. In a large caliber gun having a stationary carriage for supporting a recoiling gun tube terminating in a breech ring including a vertically slidable breechblock adapted upon being unlocked to drop to a fully open position, a rectangular housing depending from the underside of the breech ring forwardly of the breechblock and provided with a mounting lug at either end thereof, a hollow shaft journaled in the mounting lug, an actuating lever connecting the breechblock with the hollow shaft, and a torsion leaf spring contained within the hollow shaft with one end fixedly retained therein, the improvement in the means for energizing and releasing the torsion leaf spring comprising, a crank rotatably mounted in one end of the shaft in connection with the free end of the torsion leaf spring, a follower pin projecting from the outer side of said crank, a bracket fixed to the stationary carriage to project rearwardly therefrom and terminate in a substantially hook-shaped end disposed below the breech ring and rearwardly of said crank follower pin, the forward face of said hook-shaped bracket end having an upwardly and rearwardly inclined cam surface engageable with follower pin during the initial recoil travel of the breech ring whereby said crank is rotated to energize the torsion leaf spring, a housing fixed to the side of the breech ring and provided with an outwardly projecting stud, a latch pivotally mounted on said projecting stud in position to engage with said crank follower pin at the conclusion of the rotation imparted to said crank for retention thereof against the release of the energy stored in the torsion leaf spring, a locking slot formed in the exterior periphery of the end of the hollow shaft containing said crank, a spring-biased retractable plunger vertically seated in said housing on the side of the breech ring in position to engage in said locking slot whereby said shaft is retained against rotation during the recoil travel of the breech ring, means operable during the counterrecoil travel of the breech ring for lifting said plunger out of engagement with said locking slot to permit the rotation which is imparted to the shaft as the breechblock drops to the open position thereof in response to gravity forces, a rearwardly extending finger on said carriage bracket disposed to contact the upper end of said latch during the portion of the counterrecoil of the breech ring following the opening of the breechblock whereby said latch is pivoted to release said follower crank pin therefrom and thereby free said crank for the rotation imparted thereto by the stored energy of the torsion leaf spring, and means for transferring the rotation of said crank to the hollow shaft for operating the breechblock actuating lever to lift the breechblock to the closed position thereof.

10. The combination defined in claim 9 wherein said latch is a foot-shaped member having an arcuate guide slot centrally formed therethrough for passage of said crank follower pin, said guide slot originating at the toe end of said latch and terminating in a curved offset portion at the heel end thereof, and a coil spring having one end connected to said latch above the mounting stud therefor and the other end connected to said mounting stud whereby said latch is biased to displace said curved offset portion therein into engagement with said crank follower pin and prevent the release of the energy stored in the torsion leaf spring.

11. The combination defined in claim 9 wherein said means for lifting said retractable plunger out of engagement with said locking slot in the hollow shaft comprises an outwardly projecting cam surface on the exterior periphery of said crank, a rearwardly extending release lever pivotally mounted in said fixed bracket projecting from the stationary carriage and provided with a roller on one side thereof disposed in the counterrecoil path of said cam surface on said crank, and a roller projecting outwardly from the side of said retractable plunger whereby the pivotal movement imparted to said release lever during the counterrecoil travel of said crank is transferred to said roller on said retractable plunger to provide the required lifting thereof.

12. The combination defined in claim 9 wherein said means for transferring the rotation of said crank to the hollow shaft during the release of the energy stored in the torsion leaf spring comprises, a lug projecting outwardly from the end of the hollow shaft, and a reduced diameter section extending along a portion of the exterior periphery of said crank to form a transverse shoulder in the rotative path of said hollow shaft lug.

13. The combination defined in claim 9 including a manual charging handle having a ring-shaped lower end rotatably mounted on the hollow shaft adjacent said crank, means for releasably latching the upper end of said charging handle to the side of the breech ring in an inactive position, cam means on said ring-shaped handle end for lifting said retractable plunger out of engagement with the hollow shaft to unlock the breechblock, a dog projecting from the side of said ring-shaped handle end, the hollow shaft having an enlarged diameter end including an arcuate recess in the inner side thereof for passage of said dog and a shoulder at the end of said arcuate passage whereby the rotation of the ring-shaped handle end is transferred to the hollow shaft subsequent to the unlocking of the breechblock to effect the lowering thereof to the open position, the hollow shaft having a lug projecting from said enlarged diameter end, and said crank having a transverse shoulder thereon engageable by said projecting lug whereby the rotation imparted by said handle to the hollow shaft is simultaneously transferred to said crank to energize said torsion leaf spring.

14. The combination defined in claim 13 including a lateral arm projecting from the outer side of said ringshaped end of said charging handle, a detent plunger mounted in the outer end of said arm, a coil spring normally retracting said detent plunger to prevent protrusion thereof from the underside of said arm, and a notch in said enlarged diameter end of the hollow shaft positioned to receive said detent plunger when manually depressed against said spring whereby the return of said charging handle to the latched inactive position thereof can be utilized to lift the breechblock to the closed position thereof in the event of malfunction of the torsion leaf spring.

15. The combination defined in claim 13 including a stud projecting radially from the ring-shaped lower end of said charging handle, and a bar extending outwardly from said housing on said breech ring in the rotative path of said projecting stud to limit the manual rotation of the charging handle.

No references cited.

BENJAMIN A. BORCHELT, Primary Examiner.

S. C. BENTLEY, Assistant Examiner. 

1. IN A LARGE CALIBER GUN HAVING A STATIONARY CARRIAGE SUPPORTING A RECOILING BREECH INCLUDING A VERTICALLY SLIDABLE BREECHBLOCK ADAPTED UPON THE UNLOCKING THEREOF TO DROP TO A FULLY OPEN POSITION, AND TORSION LEAF SPRING MEANS DEPENDING FROM THE BREECH FOR RETURNING THE BREECHBLOCK TO THE CLOSED POSITION THEREOF, THE IMPROVEMENT IN THE MEANS FOR WINDING AND UNWINDING THE TORSION LEAF SPRING MEANS, COMPRISING A ROTATABLE CRANK CONNECTED TO ONE END OF THE TORSION LEAF SPRING MEANS, A FOLLOWER PROJECTING LATERALLY FROM THE SIDE OF SAID CRANK, A CAM SURFACED FIXED TO THE STATIONARY CARRIAGE IN POSITION TO ENGAGE WITH SAID FOLLOWER DURING THE INITIAL RECOIL TRAVEL OF THE BREECH, A LATCH PIVOTALLY MOUNTED TO THE BREECH IN POSITION TO ENGAGE WITH SAID FOLLOWER AT THE CONCLUSION OF THE ROTATION IMPARTED TO SAID CRANK AND THEREBY PREVENT UNWINDING OF THE TORSION LEAF SPRING MEANS, MEANS FOR LOCKING THE BREECHBLOCK IN THE CLOSED POSITION THEREOF DURING THE ENTIRE RECOIL TRAVEL OF THE BREECH AND DURING THE COUNTERRECOIL TRAVEL THEREOF PRIOR TO THE PASSAGE OF SAID FOL- 